i am new to lammps and i didn’t get your point. I attached my input script below. **If it’s possible to check** then please check it. but when i used ready-made hcp lattice command, then box length was not changing so much during minimization and equilibration. now for custom lattice command, box length is increasing by 10-15 times. I have doubt on given basis for hcp. but i think it’s right. here is my input script.

#-----------------Initialize Simulation--------------------

clear

units metal

dimension 3

boundary p p p

atom_style atomic

atom_modify map array

variable xlatparam equal 3.23310

variable ylatparam equal sqrt(3)

variable zlatparam equal 1.5926

#----------------Atomistic Structure-----------------------

lattice custom {xlatparam} a1 1.0 0.0 0.0 a2 0 {ylatparam} 0 a3 0 0 ${zlatparam} basis 0.0 0.0 0.0 basis 0.5 0.5 0.0 basis 0.5 0.83333333333 0.5 basis 0.0 0.33333333333 0.5 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1

# x [2 -1 -1 0] y [-1 2 -1 0] z [0 0 0 1]

region whole block -42.00 42.00 -42.00 42.00 -71.06 71.06 units box

create_box 1 whole

create_atoms 1 region whole

#----------------Interatomic Potential---------------------

pair_style eam/alloy

pair_coeff * * Zr.eam.alloy Zr

neighbor 2.0 bin

neigh_modify delay 10 check yes

#----------------Define Setting---------------------------

compute csym all centro/atom 12

compute eng all pe/atom

compute eatoms all reduce sum c_eng

#-----------------Basic Variable--------------------------

# for box length and lattice spacing

variable z1 equal xlat

variable z2 equal ylat

variable z3 equal zlat

variable L1 equal lx

variable L2 equal ly

variable L3 equal lz

#----------------Minimization---------------------------

reset_timestep 0

fix 1 all box/relax iso 0.0 vmax 0.001

# printing different thermo quantities during minimization

thermo 10

thermo_style custom step lx ly lz press pxx pyy pzz pe temp c_eatoms

min_style cg

minimize 1e-25 1e-25 8000 10000

unfix 1

# printing lattice parameter

print “lattice spacing : {z1},{z2},${z3};”

# printing box length

print “box Length : {L1},{L2},${L3};”

#--------------Equilibration---------------------------

reset_timestep 0

timestep 0.001

# setting temperature of the system to 300 kelvin

velocity all create 300 12345 mom yes rot no

fix 2 all npt temp 300 300 0.16 iso 0 0 0.16 drag 1

# printing different thermo quanities during minimization

thermo 1000

thermo_style custom step lx ly lz press pxx pyy pzz pe temp

run 80000

unfix 2

# printing lattice parameter

print “lattice spacing : {z1},{z2},${z3};”

# printing box length

print “box Length : {L1},{L2},${L3};”

# printing initial box length

variable tmp equal “lz”

variable L0 equal {tmp}
print "Initial Length, L0 = {L0};"

#---------------Deformation---------------------------

reset_timestep 0

timestep 0.001

fix 3 all npt temp 300 300 0.16 x 0 0 0.16 y 0 0 0.16 drag 1

# defining strain rate for deformation

variable srate equal 1.0e9

variable srate1 equal “v_srate / 1.0e12”

fix 4 all deform 1 z erate ${srate1} units box remap x

# printing strain and stress in a single file

variable strain equal “(lz - v_L0)/v_L0”

variable p1 equal “v_strain”

variable p2 equal “-pxx/10000”

variable p3 equal “-pyy/10000”

variable p4 equal “-pzz/10000”

thermo 10000

thermo_style custom step v_strain temp v_p2 v_p3 v_p4 press

run 200000

unfix 3

unfix 4

# printing lattice parameter

print “lattice spacing : {z1},{z2},${z3};”

# printing box length

print “box Length : {L1},{L2},${L3};”

#------------------Simulation Done-----------------------

print “All Done”

thanks